Transforming growth factor-beta1 induces microvascular abnormalities through a down-modulation of neural cell adhesion molecule in human hepatocellular carcinoma

Abstract

Hepatocellular carcinoma (HCC) is a very angiogenic and malignant cancer. Conventional chemotherapy is poorly effective because of the abnormal structural organization of HCC-infiltrating vessels. In previous work, we demonstrated that HCC angiogenesis is driven by transforming growth factor beta-1(TGF-b1)/CD105 axis, stimulating liver-derived microvascular endothelial cells (Ld-MECs) migration. As TGF-b1 also affects mural cells (MCs) recruitment and maturation, we asked whether it may contribute to HCC-induced vascular abnormalities. HCC and adjacent non-neoplastic liver (nNL) biopsies obtained from 12 patients were analyzed by immunohistochemistry for angiogenic markers CD105, TGF-b1, CD44 and vascular endothelial growth factor-a (VEGFa) and for MC markers NG2, a-smooth muscle actin (aSMA) and neural cell adhesion molecule (NCAM). The same markers were also investigated by immunocytochemistry on cultured HCC-derived stromal cells (HCC-StCs) and nNL-derived StCs (nNL-StCs) isolated from the same liver biopsies. Angiogenic factors released by StCs were analyzed by ELISA and the interaction between StCs and Ld-MECs by adhesion assay. Compared with nNL, HCC biopsies showed increased angiogenic markers and aSMA that was localized in vessels. By contrast, NG2 and NCAM were substantially localized in tumor cells but absent in vessels and stroma. Cultured HCCStCs showed less expression of NG2, aSMA and NCAM. They also demonstrated a lower capacity to release angiogenic factors and adhered on Ld-MECs. HCC-StCs and nNL-StCs treated with TGF-b1 or with of HepG2 (a human hepatoma cell line) derived conditioned medium (CM), down-modulated NCAM expression, whereas anti-NCAM antibodies significantly reduced the adhesion of StCs to Ld-MECs. By further blocking TGF-b1 with anti-TGF-b1 antibodies or with Ly-364947 (a specific inhibitor TGF-b1-receptor) adhesion to Ld-MECs and NCAM expression respectively was partially restored. TGF-b1 contributes to HCC-induced vascular alterations by affecting the interaction between HCC-StCs and Ld-MECs through a down-modulation of NCAM expression. A growing tumor recruits new blood vessels to ensure a sufficient quantity of nutrients and oxygen necessary for cancer cell survival and proliferation.1 During this process, neoformed capillaries undergo abnormal maturation 2 and vascular abnormalities are often observed in tumor, mainly involving either the composition of the basement membrane or mural cells (MCs) content. 3,4 To this regard, pericytes and smooth muscle cells (SMCs) are fundamental to determine an

Tumor markers for hepatocellular carcinoma

“…The level of serum TGF-β1 has been reported to be elevated in HCC patients compared with healthy adults or patients with non-malignant liver disease (48). It could induce microvascular abnormalities through the downregulation of neural cell adhesion molecules in human HCC (49). TGF-β1 and TGF-β1 mRNA may be used as sensitive indicators to diagnose HCC which is induced by HBV, with the sensitivity and specificity being 89.5 and 94.0%, respectively, when TGF-β1 is >1.2 μ g/l (50).…”

TGF-β1 signaling pathway serves a role in HepG2 cell regulation by affecting the protein expression of PCNA, gankyrin, p115, XIAP and survivin

“…A number of signaling pathways, including the transforming growth factor β (TGF-β)/mothers against decapentaplegic homolog (1), proto-oncogene Wnt/β-catenin (2), rat sarcoma GTPase/mitogen-activated protein kinase (MAPK) (3), phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) (4), c-Jun N-terminal kinase (JNK)/signal transducer and activator of transcription (STAT) (5,6), hedgehog and tumor protein 53 transduction pathways, serve key roles in the pathogenesis of liver cancer. Among these signaling pathways, the TGF-β signaling pathway is one of the most important (1).…”

Identification of the Genes Chemosensitizing Hepatocellular Carcinoma Cells to Interferon-α/5-Fluorouracil and Their Clinical Significance

“…In the present study, TGFB1 mRNA was not increased by the infection with Ad-TGFBR2. This result could be explained as follows: Because TGF-β is a pleiotropic cytokine, the drug-induced TGFB1 expression may provide an advantage for cancer cell survival, possibly in an endocrine fashion in vivo , such as immunosuppression and angiogenesis [43], [44]. Therefore, our observation suggests that TGFBR2 expression level may be a critical factor to determine the fate of the role of TGF-β in cancer cells.…”